CAP168, Appendix 3D
3 Clearance Techniques
3.1 Whenever possible, the full length and width of runways should be cleared
completely. Mechanical snow clearing equipment, such as blowers, sweepers,
ploughs and rotary brushes, should form the main part of the snow clearance
equipment used at most large aerodromes. As far as practicable, clearance
techniques employed should prevent the build-up of snow banks. Where this is
unavoidable, every effort should be made to restrict snow banks to such a height and
distance apart as to ensure safe manoeuvring of the most critical aircraft, in this
context, normally using the aerodrome (see Chapter 3, paragraph 11.2.5).
3.2 Slush and associated standing water should be cleared whilst it is forming. Clearance
may have to be repeated at intervals and some interruption of operations may be
inevitable.
3.3 Chemicals used for clearing or preventing the formation of ice should be fit for the
purpose, non-toxic and should have no detrimental effects on aircraft, aerodrome
surfaces, or the friction value of aerodrome pavements. Salt is a particularly corrosive
chemical and should be employed only where its use is essential to the prevention of
contaminant build-up around edge drains.
4 Operational Priorities for the Treatment and Clearance of Movement
Areas
4.1 Aerodrome licence holders should ensure that all parts of the movement area that are
in use have adequate surface friction levels, especially during winter operations.
4.2 Where contamination exists, licence holders should determine the level of treatment
and clearance needed and the order of priority in which it should take place. The order
of priority will depend upon many factors; however, it should be a general policy to
treat and clear in the following order:
a) runway(s) in use, including rapid exits and starter extensions;
b) all runway holding areas, taxiways and aprons that are to be used;
c) all other areas and roads.
Of relevance yesterday:
5.3 Snow Banks
5.3.1 The height of snow banks and their distance apart shall be reported as soon as a situation arises that these affect safe manoeuvring by the most critical aircraft, in this context, normally using the aerodrome.
Details of acceptable snow bank profiles for
certain large aircraft are given at paragraph 11.2.5 of Chapter 3.
http://www.caa.co.uk/docs/33/CAP168.PDF
For the perennial Manchester Moaners, take heart from the fact DUS was closed for 6 hours, CDG had 40% of its flights cancelled yesterday, and today is running at 50% capacity with 20% of today's flights already cancelled.